Corn is a tremendous bait for carp and trout alike! It's been used for decades in the UK, to great effect. In fact, back in the late 70's early 80's there were a number of waters where corn had been overused and the fish had started to clue into it, so what people did was to dye it with red food colouring and add a strawberry flavouring to it. Deadly method with all of those weary fish turning on to it again! The most economical (i.e. cheaper than canned corn niblets) corn to use is frozen corn.
It is not an illegal bait here, as long as it isn't used on bait ban waters! However it must be remembered that raw corn/dry corn must never be introduced into a water as it swells when it starts to take on water and if this happens inside a fish's belly.... I'm sure you can imagine the consequences!
Have fun fishing with corn!